This invention relates to a paper feeder used with a recording apparatus such as a printer for feeding sheet-like paper stacked on a hopper, and in particular to a paper feeder comprising a paper returner for returning an overlappedly transported sheet of paper to the hopper, the paper returner having a function of separating and feeding sheets of paper one by one.
A paper feeder used with a recording apparatus comprises two paper feeding rollers placed in a paper width direction, the one paper feeding roller being fixedly placed on one side edge side, and the other being built in an edge guide and semi-fixedly placed movably matching the paper width. A base end of the hopper is attached rotatably to a shaft at a right angle to the entry direction such that the whole of paper in the width direction is moved up or down at the same time by a cam mechanism associated with rotation of the paper feeding roller. A pivotable separation pad holder is provided with a separation pad to separate the sheets one by one from the hopper and feed each sheet.
When paper is abutted against the paper feeding roller, and at the same time, the separation pad is pressed against the paper feeding roller as the hopper moves up, the top sheet of paper is separated and fed. When the sheet arrives at a transport roller and skew removal is terminated, the paper feeding roller is rotated and stopped at a home position. Meanwhile, positioning is performed such that a distance between a leading edge of the paper sheet and a recording head is made constant is performed, and then print is started. When the paper feeding roller is stopped at the home position, a gap is formed between the paper feeding roller and the separation pad, but a part of the sheet being printed exists. At this time, another sheet overlappedly sent enters the gap, and two or more overlapped sheets may also be fed in conjunction with the sheet being printed in some cases. As a measure against such trouble, an idle roller is usually pressed against the separation pad. When a sheet being printed exists between the paper feeding roller and the separation pad, it is pressed against the separation pad by the idle roller, whereby entry of the sheets overlappedly sent is prevented. Each sheet whose entry is blocked is pushed and returned to the hopper by operating a paper return lever (paper returner) after the print terminates.
This related paper feeder comprises the paper feed rollers moved matching the paper width and thus has a large number of parts and also has a complicated structure. Since the paper returning operation is performed after print, the next paper feed operation cannot be started until the paper returning operation terminates, and thus the time interval between the print termination of one sheet and the print start of another sheet (throughput) is prolonged. Further, since the sheet being printed is pressed against the idle roller, a contact load with the sheet occurs and leads to a load of a motor drive system, etc.
It is therefore an object of the invention to provide a paper feeder with the reduced number of parts and a simplified structure for reducing costs and improved in straight-feeding property of paper from a hopper to a paper transporting passage.
It is another object of the invention to provide a paper feeder capable of performing the paper returning operation during printing.
In order to achieve the above objects, according to the present invention, there is provided a paper feeder, for feeding a sheet of paper to a transporting path extending to a recording apparatus, comprising:
a paper feeding roller, provided in the vicinity of a first widthwise end of the transporting path;
a hopper, for stacking a plurality of sheets of paper, including:
an aligning face, on which leading ends of the stacked sheets are abutted to be aligned with each other, the aligning face being narrowed from a first side end thereof to a second side end thereof, the first side end being in the vicinity of the first widthwise end of the transporting path, and the second side end being in the vicinity of a second widthwise end of the transporting path;
a guide face, provided on the first side end of the aligning face so as to extend parallel with the transporting path; and
a hopper member, pivotably supported on the second side end of the aligning face in a cantilevered manner, so as to move on the aligning face such that distance change in accordance with the number of sheets stacked thereon in the first widthwise end side of the transporting path with respect to the paper feeding roller becomes larger than that in the second widthwise end side of the transporting path;
a paper returner, placed in the vicinity of an end portion of the hopper which faces the paper feeding roller, so as to be pivotable between a first position where the paper returner constitutes a part of the paper transporting passage, and a second position where the paper returner is isolated from the paper transporting passage; and
a first paper retainer, provided on the first surface of the paper returner in the vicinity of the guide face of the hopper, wherein: the paper returner is placed at the first position so that a top sheet of paper in the hopper is abutted against the paper feeding roller, and is separated from other sheets of paper by the separation pad; and
wherein the paper returner is placed at the second position so that a first face of the paper returner returns sheets of paper, which are entered in the paper transporting passage together with the sheet of paper to be fed, to the hopper.
In this configuration, since the hopper member is pivotably supported on the aligning face in the opposite side to a side the single paper feeding roller is provided, the number of parts can be reduced. Further, since a leading end of sheet overhanging from the aligning face to the paper feeding roller is prevented from advancing to the transporting path by the first paper retainer, the sheet enters the transporting passage straight and can be fed stably.
Preferably, the paper feeder further comprises a separation pad, provided on the first face of the paper returner, the separation pad having a friction coefficient which is higher than a friction coefficient of the first face of the paper returner.
In this configuration, the separation pad is attached to the paper returner, so that the number of parts can be decreased and the structure can be simplified for reducing costs as compared with the case where the separation pad holder and the paper return lever are provided separately as in the related paper feeder.
Preferably, the paper feeder further comprises an urging member, which urges the paper returner toward the second position. Here, the paper feeding roller includes a first portion which urges the first face of the paper returner toward the first position, against an urging force of the urging member.
In this configuration, the first face of the paper returner is always abutted against the paper feeding roller, and paper pressing and paper returning operations of the paper returner are made reliable.
Preferably, the first paper retainer is a sheet member having a higher friction coefficient than the first face of the paper returner.
In this configuration, the leading end of sheet does not slip and the orderly stacking is held reliably.
Preferably, the paper feeder further comprises a second paper retainer, provided in the vicinity of the pivotal center of the hopper member, the second retainer having a support face for supporting a part of sheets stacked on the hopper member.
In this configuration, since the leading end of sheet overhanging from the aligning face to the paper feeding roller is also supported in the vicinity of the pivotal center of the hopper member by the second paper retainer, the sheet is more reliably prevented from advancing to the transporting path.
Here, it is preferable that the support face of the second paper retainer is narrowed from a side closer to the pivotal center of the hopper member to a side closer to the paper feeding roller.
In this configuration, since restraining force of the paper feeding roller becomes large from the pivotal center to the free end of the hopper member, when the paper feeding is performed, particularly, firm paper such as an OHP sheet is easily caught in the second paper retainer. However, the support face is narrowed on the paper feeding roller side, whereby if paper is restrained by the paper feeding roller at a local point, it smoothly climbs over the second paper retainer and is fed reliably.
Also, it is preferable that the support face of the second paper retainer is placed such that a leading end of the sheet in the vicinity of the pivotal center of the hopper member is abutted thereon when the paper retainer is placed at the first position.
In this configuration, since the leading end of sheet on the pivotal center of the hopper member side is supported by the second paper retainer at the same time that the restraining force on the paper feeding roller side is increased as the paper returner is placed in the first position, so that paper enters the paper transporting passage straight without skew.
According to the present invention, there is also provided a paper feeder, for feeding a sheet of paper to a transporting path extending to a recording apparatus, comprising:
a paper feeding roller, provided in the vicinity of a first widthwise end of the transporting path;
a hopper, for stacking a plurality of sheets of paper, including:
an aligning face, on which leading ends of the stacked sheets are abutted to be aligned with each other, the aligning face being narrowed from a first side end thereof to a second side end thereof, the first side end being in the vicinity of the first widthwise end of the transporting path, and the second side end being in the vicinity of a second widthwise end of the transporting path;
a guide face, provided on the first side end of the aligning face so as to extend parallel with the transporting path; and
a hopper member, pivotably supported on the second side end of the aligning face in a cantilevered manner, so as to move on the aligning face such that distance change in accordance with the number of sheets stacked thereon in the first widthwise end side of the transporting path with respect to the paper feeding roller becomes larger than that in the second widthwise end side of the transporting path;
a paper returner, placed in the vicinity of an end portion of the hopper which faces the paper feeding roller, so as to be pivotable between a first position where the paper returner constitutes a part of the paper transporting passage, and a second position where the paper returner is isolated from the paper transporting passage; and
a first paper retainer, provided in the vicinity of the pivotal center of the hopper member, the second retainer having a support face for supporting a part of sheets stacked on the hopper member.
wherein the paper returner is placed at the first position so that a top sheet of paper in the hopper is abutted against the paper feeding roller, and is separated from other sheets of paper by the separation pad; and
wherein the paper returner is placed at the second position so that a first face of the paper returner returns sheets of paper, which are entered in the paper transporting passage together with the sheet of paper to be fed, to the hopper.
Preferably, the paper feeder further comprises a separation pad, provided on the first face of the paper returner, the separation pad having a friction coefficient which is higher than a friction coefficient of the first face of the paper returner.
Preferably, the paper feeder further comprises an urging member, which urges the paper returner toward the second position. Here, the paper feeding roller includes a first portion which urges the first face of the paper returner toward the first position, against an urging force of the urging member.
Preferably, the support face of the first paper retainer is narrowed from a side closer to the pivotal center of the hopper member to a side closer to the paper feeding roller.
Preferably, the support face of the first paper retainer is placed such that a leading end of the sheet in the vicinity of the pivotal center of the hopper member is abutted thereon when the paper retainer is placed at the first position.
Preferably, the paper feeder further comprises a second paper retainer, provided on the first surface of the paper returner in the vicinity of the guide face of the hopper.
Here, it is preferable that the second paper retainer is a sheet member having a higher friction coefficient than the first face of the paper returner.